Method of production of product acetone of high stability to oxidation

Abstract

Disclosed is a method for the production of product acetone of higher oxidation stability where the product acetone is produced by a multi-step rectification process in the presence of alkali catalyst. The embodiments of the method of present invention utilize a two-column and a one-column scheme of product acetone rectification from an acetone stream. In a two-column embodiment of the present invention, acetone is taken off in a vapor phase as a side-draw in a first column and directed to a partial condenser wherein it is separated into liquid and vapor phases with a simultaneous feed of aqueous sodium hydroxide solution to the first column above the feed tray. The vapor phase of the partial condenser is forwarded to a second column where the product acetone is rectified and then removed overhead, the bottom products are recycled to the first column feed, and the liquid phase of the partial condenser is treated with alkali and recycled either to the first column or to a neutralization stage of cumene hydroperoxide cleavage products. In a one-column embodiment of the present invention, acetone is taken off in the vapor phase overhead and directed to the partial condenser with the simultaneous feed of the aqueous sodium hydroxide solution above the feed tray. Product acetone is then condensed from the vapor phase and removed.

We claim:  
     
       1. A rectification method, for producing high purity acetone from CHP cleavage products, implemented in a multi-stage process system, the system comprising a first, a second, and a third column, the method comprising the steps of; 
       (a) producing an acetone fraction from a first column overhead, the first column functioning without reflux;  
       (b) providing a first partial condenser between the first and the second columns and delivering overhead products of the first column to said first partial condenser as a vapor phase, wherein from about 2 to about 10% relative products are condensed in said partial condenser;  
       (c) directing said condensed products to recycle to a feed of the first column and directing a non-condensed phase of said products comprising crude acetone to a feed of the second column;  
       (d) directing a take-off of an aldehyde fraction from the second column overhead and directing of this fraction to a neutralization stage;  
       (e) providing a second partial condenser between the second and the third columns and directing a take-off of the second column vapor phase as a side-draw to said second partial condenser to produce an acetone vapor phase and an acetonic liquid phase;  
       (f) directing said acetone vapor phase from said second partial condenser to a third column feed, treating said acetone liquid phase with an alkali solution and returning said acetone liquid phase to said first second column and to said neutralization stage of cumene hydroperoxide cleavage products; and  
       (g) removing a take-off of product acetone from the third column overhead, said product acetone having a high stability to oxidation, having a value of permanganate time from about 8 to about 70 hours.  
     
     
       2. The method of claim  1 , further comprising the step of: 
       (h) maintaining a weight ratio of liquid and vapor phases in the second partial condenser is from about 1:10 to about 1:100.  
     
     
       3. The method of claim  1 , further comprising the step of: 
       (i) recycling liquid products of the second partial condenser having unreacted aldehydes, aldols and acetone to said second column feed.  
     
     
       4. The method of claim  3 , wherein the degree of aldols separation in the second partial condenser is higher than 90%, further comprising the step of: 
       (j) directing said aldols to a neutralization stage.  
     
     
       5. The method of claim  1 , wherein the second column comprises a feed tray, further comprising the step of: 
       (k) feeding an aqueous NaOH solution to the second column above said feed tray.  
     
     
       6. The method of claim  5 , further comprising the step of: 
       (l) maintaining crude acetone/NaOH ratio on a 100% NaOH basis within the range from about 0.0036 to about 0.006 per ton of acetone.  
     
     
       7. The method of claim  1 , further comprising the step of: 
       (m) controlling permanganate time value of product acetone from about 8 to about 70 hours by selectively altering a value of liquid and vapor phases ratio of the second partial condenser.  
     
     
       8. The method of claim  1 , further comprising the step of: 
       (n) setting a reflux number at the third column is equal to about 2.5 to about 5.  
     
     
       9. The method of claim  1 , further comprising the step of: 
       (o) maintaining an atmosphere pressure in the first column and in the second column and maintaining vacuum of about 400 to about 600 Hg in the third column.  
     
     
       10. The method of claim  1 , further comprising the step of: 
       (p) maintaining different pressure is in said first and said second partial condensers.  
     
     
       11. The method of claim  10 , wherein said step (p) comprises the step of: maintaining an atmospheric pressure in said first partial condenser and maintaining a vacuum from about 600 to about 650 Hg in said second partial condenser. 
     
     
       12. The method of claim  1 , further comprising the step of: 
       (q) maintaining acetone content in a bottom of the third column equal to or below about 0.4 weight %.  
     
     
       13. The method of claim  1 , wherein cumene concentration in said first column feed is from about 1 to about 40 weight %. 
     
     
       14. The method of claim  1 , wherein water concentration in the first column feed is from about 2 to 15 weight %. 
     
     
       15. A method for rectification of product acetone with a high stability to oxidation from cumene hydroperoxide cleavage products, the method being implemented in plurality of rectification columns, said method comprising the steps of: 
       (a) taking off an acetone fraction overhead from an acetone and phenol streams rectification column;  
       (b) directing said acetone fraction through a first partial condenser to separate said acetone fraction into a condensed acetone fraction product, and an uncondensed acetone fraction product;  
       (c) directing condensed acetone fraction product to recycle to said acetone and phenol streams rectification column;  
       (d) directing said uncondensed acetone fraction product to a first product acetone rectification column having a feed tray;  
       (e) when the plural rectification columns exceed two columns, removing an aldehyde fraction overhead from said first product acetone rectification column and directing said aldehyde fraction to a neutralization stage;  
       (f) when the plural rectification columns exceed two columns, directing side-draw products from said first product acetone rectification column to a second partial condenser, to separate said side-draw products into an acetone liquid phase and an acetone vapor phase, otherwise, when the plural rectification columns are two columns, directing overhead products from said first product acetone rectification column to a second partial condenser, to separate said overhead products into an acetone liquid phase and an acetone vapor phase;  
       (g) simultaneously with said step (f), introducing an aqueous sodium hydroxide solution to said first product acetone rectification column above said feed tray;  
       (h) treating said acetone liquid phase with an alkali solution and returning said acetone liquid phase to said first product acetone rectification column and to a neutralization stage of cumene hydroperoxide cleavage products;  
       (i) introducing said acetone vapor phase to a second product acetone rectification column and separating said acetone vapor phase into water and product acetone; and  
       (j) removing said product acetone from said second product acetone rectification column.  
     
     
       16. The method of claim  15 , wherein at said step (b) said condensed acetone fraction product comprises from about 2% to about 10% relative of said acetone fraction. 
     
     
       17. The method of claim  15 , wherein when the plural rectification columns exceed two columns, said step (f) further comprises the step of separating said side draw products into said acetone liquid phase and said acetone vapor phase at a weight flow ratio ranging from about 1:10 to about 1:100, correspondingly, and wherein when the plural rectification columns are two columns, said step (f) further comprises the step of separating said overhead products into said acetone liquid phase and said acetone vapor phase at a weight flow ratio ranging from about 1:10 to about 1:100, correspondingly, and wherein. 
     
     
       18. The method of claim  15 , wherein at said step (g) said aqueous sodium hydroxide is a NaOH solution delivered in a quantity from about 0.0036 ton to about 0.006 ton per one ton of acetone, wherein said quantity of NaOH is selected with reference to a required value of a permanganate test ranging from 8 to 70 hours. 
     
     
       19. The method of claim  15 , wherein said first and said second acetone rectification columns operate under one of: atmospheric pressure and a vacuum of about 400 to about 650 mm Hg. 
     
     
       20. A method for rectification of product acetone with a high stability to oxidation from cumene hydroperoxide cleavage products, the method being implemented in two rectification columns, said method comprising the steps of: 
       (a) taking off an acetone fraction overhead from an acetone and phenol streams rectification column;  
       (b) directing said acetone fraction through a first partial condenser to separate said acetone fraction into a condensed acetone fraction product, and an uncondensed acetone fraction product;  
       (c) directing condensed acetone fraction product to recycle to said acetone and phenol streams rectification column;  
       (d) directing said uncondensed acetone fraction product to a product acetone rectification column having a feed tray;  
       (e) directing overhead products in a vapor phase from said first product acetone rectification column to a second partial condenser, to separate said overhead products into an acetone liquid phase and an acetone vapor phase and to condense said acetone vapor phase into  
       (f) simultaneously with said step (e), introducing an aqueous sodium hydroxide solution to said first product acetone rectification column above said feed tray;  
       (g) treating said acetone liquid phase with an alkali solution and returning said acetone liquid phase to said product acetone rectification column and to a neutralization stage of cumene hydroperoxide cleavage products; and  
       (h) removing said product acetone from said product acetone rectification column.  
     
     
       21. The method of claim  20 , wherein at said step (b) said condensed acetone fraction product comprises from about 2% to about 10% relative of said acetone fraction. 
     
     
       22. The method of claim  20 , wherein at said step (e) said overhead products are separated into said acetone liquid phase and said acetone vapor phase at a weight flow ratio ranging from about 1:50 to about 1:150, correspondingly. 
     
     
       23. The method of claim  20 , wherein at said step (f) said aqueous sodium hydroxide is a NaOH solution delivered in a quantity from about 0.0036 ton to about 0.006 ton per one ton of acetone, wherein said quantity of NaOH is selected with reference to a required value of a permanganate test ranging from 4 to 40 hours. 
     
     
       24. The method of claim  20 , wherein said product acetone rectification column operates under one of: atmospheric pressure and a vacuum of about 400 to about 650 mm Hg. 
     
     
       25. A rectification method, for producing high purity acetone from CHP cleavage products, implemented in a multi-stage process system, the system comprising a first, a second, and a third column, the method comprising the steps of: 
       (a) producing an acetone fraction from a first column overhead, the first column functioning with a reflux ratio maintained within a range of about 2-0.7;  
       (b) providing a total condenser between the first and the second columns and delivering overhead products of the first column to said total condenser as a vapor phase to fully condense said products therein;  
       (c) in accordance with said reflux ratio, directing a first portion of said condensed products to recycle to an overhead portion of the first column, and directing a second potion of said products to a feed of the second column;  
       (d) directing a take-off of an aldehyde fraction from the second column overhead and the direction of this fraction to a neutralization stage;  
       (e) providing a partial condenser between the second and the third columns and directing a take-off of the second column vapor phase as a side-draw to said partial condenser;  
       (f) directing said vapor phase from said partial condenser to a third column feed; and  
       (g) removing a take-off of product acetone from the third columns as a side-draw, said product acetone having a high stability to oxidation, having a value of permanganate time from about 8 to about 70 hours.